/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.schemas;



import com.bff.gaia.unified.sdk.annotations.Experimental;

import com.bff.gaia.unified.sdk.annotations.Experimental.Kind;

import com.bff.gaia.unified.sdk.transforms.SerializableFunction;

import com.bff.gaia.unified.sdk.values.Row;

import com.bff.gaia.unified.sdk.values.TypeDescriptor;



import javax.annotation.Nullable;

import java.io.Serializable;



/**

 * Concrete implementations of this class allow creation of schema service objects that vend a

 * {@link Schema} for a specific type. One example use: creating a {@link SchemaProvider} that

 * contacts an external schema-registry service to determine the schema for a type.

 */

@Experimental(Kind.SCHEMAS)

public interface SchemaProvider extends Serializable {



  /** Lookup a schema for the given type. If no schema exists, returns null. */

  @Nullable

  <T> Schema schemaFor(TypeDescriptor<T> typeDescriptor);



  /**

   * Given a type, return a function that converts that type to a {@link Row} object If no schema

   * exists, returns null.

   */

  @Nullable

  <T> SerializableFunction<T, Row> toRowFunction(TypeDescriptor<T> typeDescriptor);



  /**

   * Given a type, returns a function that converts from a {@link Row} object to that type. If no

   * schema exists, returns null.

   */

  @Nullable

  <T> SerializableFunction<Row, T> fromRowFunction(TypeDescriptor<T> typeDescriptor);

}